PREVOST H3-41 Maintenance Manual page 989

FIGURE 29: FUNCTIONING OF LAVATORY
8.9 FLUSH PUSH-BUTTON
The green flush push-button is located near the
toilet. Press on push-button to actuate a pneumatic
timer located on the other side of wall. This timer
allows an electric current flow during a preset time
to a pump into the sump tank.
8.9.1 Pneumatic Timer Removal and
Installation
1. Unscrew and remove the flush push-button
locking ring.
2. Remove steel plate located on L.H. side of
pushbutton switch.
3. Remove pneumatic
opening, taking care to disconnect electric
wires.
NOTE
Care must be taken to avoid losing the spacers
installed on the mounting sleeve.
4. Reverse the above procedure to reinstall
timer. Tighten lock nut:
8.9.2 Timer Adjustment
Timer can be adjusted from 0.2 second to 3
minutes by turning the time adjustment screw
clockwise to increase time, and counterclockwise to
23038
timer through this
SECTION 23A: ACCESSORIES - H3 SERIES
decrease time. To gain access to the time adjust-
ment screw, repeat steps 1, 2 and 3 in the previous
paragraph.
8.10 FLUSH PUMP
The submersible-type flush pump is mounted inside
an enclosure in the sump tank (Figure 30). The
enclosure is provided with a screened side which,
serves as a strainer to prevent solid matters from
entering the pump.
The pump requires no periodic maintenance other
than cleaning of the strainer side using a water jet
introduced through the circular cap opening, once
the sump tank is completely drained. The pump
can run dry periodically without damage. However,
for maximum seal life, the run dry periods should
be kept to a minimum.
CAUTION
If vehicle is stored for an extended period of
time, make sure to clean the strainer as solid
matter will tend to pack, and will necessitate
replacement of strainer.
8.10.1 Flush Pump Pressure Adjustment
The flush pump is provided with a manually-
adjustable control valve mounted on the flush
pump enclosure cover and serves to limit the
flush pump output pressure. To adjust, ask an
assistant to activate the flush pushbutton and
check the liquid projection while you manually
adjust the control valve
8.11 SUMP TANK
8.11.1 Sump Tank Draining
To drain sump tank, unscrew cap a few turns
then turn drain valve handle CCW. Flush tank
and pump cage with clean water. Close drain
valve by turning handle CW.
CAUTION
The lavatory should be serviced by mainte-
nance personnel after emergency draining.
Lavatory tanks should be serviced only at
suitably equipped stations.
PA1621 Maintenance Manual All Series | Jan 2020
23